{	Problem: http://codeforces.ru/problemset/problem/25/B
	Verdict: Accepted

}
var i,n:longint; s:string;
begin
readln(n);
readln(s);
i:=3;
write(s[1],s[2]);
if odd(length(S)) then begin
    write(s[3]); 
    inc(i);
end;
while i<n do begin
    write('-',s[i],s[i+1]);
    inc(i,2);
end;
end.